In many current applications involving digital video signals, digital video signals are often desired to be coded with selected coding schemes during signal processing, storing, delivering, and/or reproducing. Even though compression may or may not be desired after coding, it is often desired that video signals can be identified individually or in groups after coding.
For example, stereoscopic video signals generally represent views of a particular scene from two perspectives such as from the right eye and left eye of a viewer. By rendering separate images of the video signals for the right and left eyes respectively, the illusion of three dimensional depth can be presented. Specifically, the left and right images are alternated rapidly on a screen. When the viewer looks at the screen through active shutter glasses, each shutter is synchronized to occlude the unwanted images and transmit the wanted images. Thus each eye sees only its appropriate perspective view. The left eye behind the left shutter sees only the left view; and the right eye behind the right shutter sees only the right view. In order to synchronize the shutter glasses to the images for different perspectives, it is desired to code the video signals. The coded images for different perspectives can be identified and differentiated by the shutter glasses.
In multi-view applications, images for different viewers can be sequentially displayed on a screen. Shutters of different viewers selectively pass wanted images and block unwanted images. Accordingly, images for such applications are desired to be coded such that shutters of different viewers can identify and differentiate the displayed images.
In some other applications, different streams of video signals/images (e.g. for different viewing purposes) are mixed and processed, stored, and/or delivered as a combined video stream. In these applications, video signals of different streams are desired to be coded such that they can be identified and differentiated during processing, storing, and/or delivering.